Q&A Hero

Q: From a consideration of the Lewis structure of the thiocyanate ion, SCN-, in which carbon has a double bond with both the sulfur and nitrogen atoms, the formal charges on the sulfur, carbon, and nitrogen atoms are, respectively,A) -1, +1, -1.B) -2, 0, +1.C) -1, 0, 0.D) -2, +1, 0.E) 0, 0, -1.

Q: Which of the following species represents an exception to the octet rule?A) BF3B) BF4-C) CH3OHD) CCl4E) PH3

Q: Which of the following Lewis structures best describes BF3?A) B) C) D) E)

Q: Which of the following has an incomplete octet in its Lewis structure? A) SO2 B) F2 C) NO2 D) ICl E) CO2

Q: In the Lewis dot formula for ICl2-, the number of lone pairs of electrons around the central iodine atom isA) 2.B) 4.C) 1.D) 3.E) 0.

Q: Which of the following molecules has an incorrect Lewis formula?A) B) C) D) E)

Q: In the Lewis formula for ClF3, how many lone pairs are around the central atom? A) 0 B) 4 C) 3 D) 2 E) 1

Q: Which species has the largest number of lone pairs of electrons around the central atom?A) XeF2B) XeF6C) XeOF4D) XeF4E) SiF62-

Q: The Lewis formula of which species does notrepresent an exception to the octet rule? A) SiF5- B) SCl6 C) SF4 D) BF3 E) CF3-

Q: The octet rule is violated by at least one atom in all the following compounds except A) SF6. B) PF6-. C) BrF5. D) ICl2-. E) SiF4.

Q: In which of the following molecules is the octet rule violated? A) SF6 B) OF2 C) ClF D) PF3 E) SiF4

Q: The Lewis structure of a molecule has a high probability of violating the octet rule if 1) the molecule has an odd number of valence electrons. 2) the central atom is surrounded by more than four atoms or eight valence electrons. 3) the central atom is from Group 2A or 3A. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1, 2, and 3

Q: Which of the following species represents an exception to the octet rule? A) SiO2 B) HBr C) SF4 D) PCl3 E) CO2

Q: The electronic structure of which of the following species cannot be adequately described by a single Lewis formula?A) CS2B) POF3C) HNNHD) NO3-E) H2NNH2

Q: Which of the following are two appropriate resonance formulas for the acetate ion, CH3CO2"?A) B) C) D) E)

Q: For each of the following species except ____, the electronic structure may be adequately described by two resonance formulas.A) O3B) SO32-C) NO2-D) C6H6E) SO2

Q: Which one of the following species is best described by writing three equivalent Lewis formulas?A) SO3B) SF4C) SO42-D) SO32-E) SOF4

Q: For the resonance hybrid of the nitrite ion, what is the average number of bonds between the nitrogen atom and an oxygen atom? A) 3/2 B) 1 C) 4/3 D) 2 E) 5/3

Q: In which of the following species is resonance most likely to take place?A) B) C) D) E)

Q: All the following statements about resonance are true except A) A single Lewis formula does not provide an adequate representation of the bonding. B) Resonance describes a more stable situation than does any one contributing resonance formula. C) Resonance describes the oscillation and vibration of electrons. D) The contributing resonance formulas differ only in the arrangement of the electrons. E) Resonance describes the bonding as intermediate between the contributing resonance formulas.

Q: The concept of resonance describes molecular structures A) that have several different geometric arrangements. B) that have delocalized bonding. C) that are formed from hybridized orbitals. D) that have different molecular formulas. E) that have electrons resonating.

Q: In the Lewis formula for the hydroxide ion, OH-, the number of lone pairs of electrons around the oxygen atom is A) 3. B) 1. C) 2. D) 0. E) 4.

Q: In the Lewis formula for hydrazinium ion, N2H5+, the total number of lone electron pairs around the two nitrogen atoms is A) 0. B) 4. C) 3. D) 1. E) 2.

Q: What is the total number of valence electrons in the sulfite ion? A) 30 B) 26 C) 24 D) 8 E) 32

Q: The total number of valence electrons in the phosphate ion is A) 32. B) 30. C) 24. D) 28. E) 26.

Q: The number of valence electrons in the nitrite ion is A) 22. B) 16. C) 23. D) 18. E) 24.

Q: The total number of valence electrons in the tetrathionate ion, S4O62", is A) 58. B) 60. C) 56. D) 54. E) 62.

Q: The number of valence electrons in the perfluoropropionate ion, , is A) 60. B) 62. C) 66. D) 80. E) 58.

Q: The total number of valence electrons in a peroxide ion, , is A) 2. B) 12. C) 14. D) 13. E) 15.

Q: How many valence electrons are there in the acetate ion, ? A) 23 B) 24 C) 36 D) 38 E) 22

Q: How many valence electrons does a nitrate ion have? A) 30 B) 28 C) 24 D) 32 E) 22

Q: What is the total number of valence electrons in the monohydrogen phosphate ion, ? A) 30 B) 28 C) 32 D) 34 E) 36

Q: How many valence electrons are there in the tetraethylammonium ion, ? A) 56 B) 32 C) 16 D) 57 E) 48

Q: What is the total number of valence electrons in the nitrosyl ion, ? A) 11 B) 13 C) 10 D) 12 E) 14

Q: What is the total number of valence electrons in the ? A) 20 B) 12 C) 16 D) 22 E) 18

Q: How many valence electrons are present in the Lewis formula for the hypochlorite ion, ? A) 20 B) 12 C) 18 D) 14 E) 16

Q: The Lewis structure for each of the following species except ____ contains a triple bond.A) N3-B) N2C) HCCHD) NO+E) O22+

Q: The Lewis structure for each of the following except ____contains at least one double bond.A) O2B) CS2C) C2H4D) NO+E) N2H2

Q: Which one of the following has a Lewis formula most similar to that of NO"?A) O2B) O22-C) O2-D) NO+E) NO

Q: Which of the following is a correct Lewis electron-dot formula for CO? A) B) C) D) E)

Q: Which of the following is a correct Lewis electron-dot formula for H2SO4?A) B) C) D) E)

Q: Which of the following Lewis formulas is incorrect?A) B) C) D) E)

Q: In the Lewis formula for difluorodiazine, N2F2, the total number of lone electron pairs around the two nitrogen atoms is A) 4. B) 0. C) 3. D) 1. E) 2.

Q: What is the total number of valence electrons in N2O4? A) 34 B) 11 C) 16 D) 17 E) 46

Q: Which of the following concerning Lewis electron-dot formulae is/are correct? 1) A Lewis electron-dot formula (Lewis structure) is identical to a structural formula. 2) The skeleton of a molecule need not be known to draw the correct Lewis electron-dot structure. 3) Lewis electron-dot formulae show the location of bonding and nonbonding electrons in three dimensional space. A) 1 only B) 2 only C) 3 only D) 1, 2, and 3 E) none of the above

Q: The Lewis formula for phosphine, PH3, has A) four lone pairs. B) four bonding pairs. C) two bonding pairs and two lone pairs. D) three bonding pairs and one lone pair. E) one bonding pair and three lone pairs.

Q: In which of the following species is there the greatest unequal sharing of the bonding electrons?A) SO3B) SO32-C) H2SD) H2OE) NH4+

Q: Which of the following bonds would be the least polar yet still be considered polar covalent? A) Mg-O B) C-O C) Si-O D) O-O E) N-O

Q: Rank the following covalent bonds in order of decreasing polarity: C-H, N-H, O-H, F-H. A) F-H, O-H, N-H, C-H B) O-H, F-H, N-H, C-H C) N-H, F-H, O-H, C-H D) C-H, N-H, O-H, F-H E) C-H, F-H, O-H, N-H

Q: Which pair of elements would form a covalent bond that is the least polar?A) S and LiB) Al and NC) O and HD) O and FE) S and Cs

Q: Which of the following concerning electronegativity is/are correct? 1) Differences in element electronegativities may be used to predict the type of bonding, ionic or covalent, in a substance. 2) The larger the differences in electronegativity between two bonded atoms the more polar the bond. 3) The electrons in a polar bond tend to spend more time around the least electronegative element. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1, 2, and 3

Q: An atom of which of the following elements has the highest electronegativity? A) K B) As C) Ba D) Si E) Br

Q: Which of the following atoms is the most electronegative? A) B B) N C) Al D) Cs E) Na

Q: The measure of the attraction that an atom has for the electrons in a chemical bond is called A) electronegativity. B) lattice energy. C) resonance energy. D) ionization energy. E) electron affinity.

Q: A bond in which an electron pair is unequally shared by two atoms is A) polar covalent. B) coordinate covalent. C) ionic. D) nonpolar covalent. E) metallic.

Q: A bond in which both electrons of the bond are donated by one atom is called ____. A) a coordinate covalent bond B) a polar covalent bond C) an ionic bond D) a double bond E) a triple bond

Q: During the formation of a chemical bond between two hydrogen atoms, which of the following statements is always true? A) Energy is released during the formation of the bond. B) A polar covalent bond is formed. C) Electrons always are between the nuclei of the atoms. D) One of the hydrogen atoms is ionized. E) Resonance stabilizes the bond.

Q: The formulas of many binary covalent compounds can be predicted on the basis A) that a bond is formed by the overlapping of two filled orbitals. B) that the number of bonds an atom can have is equal to the number of empty valence orbitals it has. C) that a bond is formed by the overlapping of atomic orbitals. D) that the number of bonds an atom can have is equal to the number of half-filled valence orbitals it can have. E) that bonding electrons are simultaneously attracted by more than one nucleus.

Q: Which of the following is the best explanation for a covalent bond? A) electrons simultaneously attracted by more than one nucleus B) an interaction between outer electrons C) the overlapping of unoccupied orbitals of two or more atoms D) the overlapping of two electron-filled orbitals having different energies E) a positive ion attracting negative ions

Q: For which of the following pairs of species is the difference in radius the greatest?A) C and FB) K+and Br-C) Li+and I-D) Na and MgE) O2-and F-

Q: Rank the following species in order of decreasing radii: K+, Cl-, Se2-, Br-. A) Br-> Se2-> Cl-> K+ B) Se2-> Br-> Cl-> K+ C) K+> Cl-> Se2-> Br- D) Br-> Cl-> Se2-> K+ E) Cl-> Se2-> K+> Br-

Q: Rank the following ions in order of decreasing ionic radius: S2-, O2-, F-, Na+, Mg2+.A) S2-, O2-, F-, Na+, Mg2+B) O2-, F-, Na+, Mg2+, S2-C) O2-, S2-, F-, Na+, Mg2+D) Mg2+, Na+, F-, O2-, S2-E) Mg2+, S2-, Na+, F-, O2-

Q: In which of the following lists do the ions not appear in order of increasing ionic radius?A) S2-< Cl-< K+B) Na+< F-< O2-C) Cl-< Br-< I-D) Li+< Na+< K+E) Al3+< Mg2+< Na+

Q: Which of the following species would you expect to have the largest radius? A) B) F C) D) E)

Q: Rank the following ions in order of decreasing atomic radii: Te2-, Te4+, Te6+.A) Te2> Te4+> Te6+B) Te6+> Te4+> Te2-C) Te4+> Te2-> Te6+D) Te2-> Te6+> Te4+E) Te4+> Te6+> Te2-

Q: Rank the following ions in order of decreasing atomic radii: Mo4+, Mo5+, Mo6+. A) Mo4+> Mo5+> Mo6+ B) Mo6+> Mo5+> Mo4+ C) Mo5+> Mo4+> Mo6+ D) Mo6+> Mo4+> Mo5+ E) Mo4+> Mo6+> Mo5+

Q: The following species, , , and , all have the same number of A) electrons. B) nucleons. C) neutrons. D) protons. E) isotopes.

Q: All of the following species are isoelectronic exceptA) O-B) NeC) N3-D) Mg2+E) F-

Q: All of the following species are isoelectronic exceptA) S2"B) K+C) Na+D) ArE) Cl-

Q: Which two species are isoelectronic?A) Na+and K+B) Al3+and NeC) P-and Ca+D) Cl-and F-E) Ca2+and Mg2+

Q: Which pair of species is isoelectronic?A) Na+and K+B) K+and Cl-C) Be2+and Na+D) Ne and ArE) Li+and Ne

Q: All of the following species are isoelectronic exceptA) Ar.B) Ca2+.C) Mg2+.D) Cl-.E) S2-.

Q: Which of the following species is isoelectronic with Kr? A) B) C) D) E) Ar

Q: Which set of ions are isoelectronic in their ground-state electron configurations?A) N, O, F, NeB) Na+, K+, Rb+, Cs+C) F-, Cl-, Br-, I-D) Mg2+, Ca2+, Sr2+, Ba2+E) N3-, O2-, Mg2+, Al3+

Q: All of the following ions have the ground-state electron configuration of a noble gas except which one?A) Ca2+B) Cl-C) Ga3+D) Al3+E) H-

Q: What is the ground-state electron configuration of ? A) B) C) D) E)

Q: What is the ground-state electron configuration of the copper(I) ion, ? A) B) C) D) E)

Q: What is the ground-state electron configuration of ? A) B) C) D) E)

Q: What is the ground-state electron configuration of ? A) B) C) D) E)

Q: What is the electron configuration of ? A) B) C) D) E)